<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    
    ul{
        list-style: none;
    }
    .box{
        width: 400px;
        margin: 0 auto;
    }
    .conten{
        width: 150px;
        height: 40px;
        background-color: skyblue;
        color: white;
        text-align: center;
        cursor: pointer;
        line-height: 40px;
    }
    .yuan{
        width: 150px;
        /* height: 80px; */
        background-color: aqua;
        color: white;
        height: 0;
        text-align: center;
        line-height: 80px;
        overflow: hidden;
        transition: all 1s linear;
    }
    li:hover .yuan{
        height: 80px;
    }
    </style>
</head>
<body>
    <div class="box">
        <ul>
            <li>
                <div class="conten">牛肉拉面</div>
                <div class="yuan">每碗100元</div>
            </li>
            <li>
                <div class="conten">牛肉拉面</div>
                <div class="yuan">每碗100元</div>
            </li>
            <li>
                <div class="conten">牛肉拉面</div>
                <div class="yuan">每碗100元</div>
            </li>
            <li>
                <div class="conten">牛肉拉面</div>
                <div class="yuan">每碗100元</div>
            </li>
        </ul>
    </div>
</body>
</html>